False positive of SC2261 (“multiple redirections compete for $FD”)

[phi-gamma]

• Rule Id: SC2261
• My shellcheck version (shellcheck --version or "online"):
• The rule's wiki page does not already cover this
• I tried on https://www.shellcheck.net/ and verified that this is
  still a problem on the latest commit

Here's a snippet or screenshot that shows the problem:

#!/usr/bin/env bash
set -euo pipefail

exec {out_fd}>/tmp/whatever

output_both () {
    echo foo
    echo bar >&2
    echo baz
    echo xyzzy >&2
}

output_both >&${out_fd} 2>&${out_fd}

Here's what shellcheck currently says:

$ shellcheck rd.sh

In rd.sh line 13:
output_both >&${out_fd} 2>&${out_fd}
            ^-- SC2261 (error): Multiple redirections compete for stderr. Use cat, tee, or pass filenames instead.
                         ^-- SC2261 (error): Multiple redirections compete for stderr. Use cat, tee, or pass filenames instead.

For more information:
  https://www.shellcheck.net/wiki/SC2261 -- Multiple redirections compete for...

Here's what I wanted or expected to see:

Nothing. The rule should not trigger.

The redirections in the example don’t “compete” for stderr or any
other fd for that matter. $out_fd refers to a file and both stdout
and stderr are correctly redirected to that file.